Detections
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Fedora 33 : xen (2021-47f53a940a)

high Nessus Plugin ID 146913

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Synopsis

The remote Fedora host is missing one or more security updates.

Description

The remote Fedora 33 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2021-47f53a940a advisory.

 - An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a guest is allowed to control whether memory accesses are bypassing the cache. This means that Xen needs to ensure that all writes (such as the ones during scrubbing) have reached the memory before handing over the page to a guest. Unfortunately, the operation to clean the cache is happening before checking if the page was scrubbed. Therefore there is no guarantee when all the writes will reach the memory. (CVE-2021-26933)

 - An issue was discovered in the Linux kernel 4.18 through 5.10.16, as used by Xen. The backend allocation (aka be-alloc) mode of the drm_xen_front drivers was not meant to be a supported configuration, but this wasn't stated accordingly in its support status entry. (CVE-2021-26934)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected xen package.

See Also

https://bodhi.fedoraproject.org/updates/FEDORA-2021-47f53a940a

Plugin Details

Severity: High

ID: 146913

File Name: fedora_2021-47f53a940a.nasl

Version: 1.3

Type: local

Agent: unix

Published: 3/1/2021

Updated: 4/12/2021

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2021-26934

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:fedoraproject:fedora:33, p-cpe:/a:fedoraproject:fedora:xen

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 2/17/2021

Vulnerability Publication Date: 2/17/2021

Reference Information

CVE: CVE-2021-26933, CVE-2021-26934